What would cause an injector to act like this....? Random p0303

So literally this has started out of nowhere, and have been getting incredibly random p0303. The truck has a very tiny bit of white smoke at startup, and idle occasionally wants to fluctuate(not like a grid heater cycle)... again only on start up.

When cold has some white smoke at light throttle, but clears around 9k psi rail. Clears about 5 mins after start. Idles very smooth, but there's a noticeable fuel knock.

The thing that's really weird is as soon as I shift out of park to drive and espedcially reverse you can see a big dip (around 550-600rpm) then it kinda recovers.

The truck has a bad solenoid pack in the trans that I know needs to be replaced and it's sitting on the shelf, just haven't had time yet. I know that the trans computer essentially sends test signals upon start up to all the solenoids in the pack,, but wouldn't think it would cause such an extensive draw from the failing solenoid to place such a demand on the system.

I performed a cylinder contribution test, and to say cylinder 3 is acting phucking crazy is an understatement. Bounces around from 75ish to 100 in waves while in park, shift in to drive while idling and 100% across the map basically. Shift back to park, then floats around 100!

I also ran an individual injector kill test and well... nothing that stuck out in plain sight....

Here's both the tests, thoughts?!

Injector kill test Cummins 6.7 on Snap on Verus. - YouTube

Injector contribution test 6.7 Cummins with snap on verus - YouTube

I know solenoid needs to be replaced, but would it cause a glitch in the injection from excess current draw?

Literally this is random as hell and can go away with just a key cycle...

Here's jist a key cycles difference.... literally back to back after truck was sitting for about 3hrs.

Mystery 6.7 idle surge... no codes present - YouTube

Mystery idle surge gone after restart.... still no code. - YouTube

(Excuse my sailor mouth in this video) poor choice and timing.:lolly:

Surprised it was able to remain idling dropping down to below 400! Definitely trans related.

Crazy erratic 6.7l Cummins idle issue with not codes - YouTube

Ended up being an occasionally sticking nozzle, and the trans solenoid was a while seperate issue that wasn't helping since it was causing the surging.

Pulled #3. Bore it down, and the pintle didn't want to freely come out of the injector. Brake cleaned the snot out of both the nozzle and pintle, let it soak over night, the flushed it out once more. Was moving beautifully in and out ofbthe nozzle after cleaning.





Got it buttoned up and fitted back on the body. Purge the lines of air and fired up stupidly smooth and zero white smoke. Turns out #3 was causing a fuel knock I had been hearing for quite sometime, and now is gone!

I highly recommend cleaning thoroughly to anyone, before you go off running to scrap a set of injectors due to a single issue. I have a bad habit of idling a lot and with that said, I regularly use power service each tank.... this was a very nasty stuck injector though.

Filtration, filtration, filtration.
Try to always use a reputable local fuel supplier and don't stop at nasty looking truck stops for fuel.

Mark.

Mark Nixon said:

Filtration, filtration, filtration.
Try to always use a reputable local fuel supplier and don't stop at nasty looking truck stops for fuel.

Mark.

Click to expand...

Here's the kicker! I retained the inline factory f/w filter assembly post my airdog 2-4g with 2 micron setup.

Like you said though, quality matters!

Had a local guy have a similar issue on a 5.9, only #1 injector locked the pintle full open and it plain would not start.
They messed with it for hours, then capped lines and found it was number 1, so they were going to just go get a new injector.
I talked them into letting me clean it and it had some dirt in it and this gray tar looking stuff.
Cleaned it all up nice, stuck it back in, ran it down the road, blew all the fuel (probably 3 or 4 GALLONS) out of the exhaust and no more issues.

The crap they are calling fuel these days, is most of the cause for the injector problems people are having.

Mark.

Lots and lots of people fill their filters at installation, which contaminates the **** out of the fuel system.

Empty/clean everything, put the filters on, and let it prime.

Not that this is the case here.

Sent from my XT1575 using Tapatalk

Mark Nixon said:

Try to always use a reputable local fuel supplier and don't stop at nasty looking truck stops for fuel.

Click to expand...

Hard to find lot lizards at reputable establishments.